Structure for a stepper

ABSTRACT

The present invention discloses an improved structure for a stepper, particularly a stepper having a restoring device, wherein an inertial gas together with hydraulic oil is filled into the hydraulic cylinder of a stepper. As the outer shell of the atom of the inertial gas is saturated with electrons, the inertial gas will be very stable in the hydraulic cylinder. When a force is applied to the piston rod of the stepper, the piston will be pushed forward to compress the inertial gas and the hydraulic oil. When the force acting on the piston is released, the inertial gas will expand, which will create a restoring force to push the piston back to the original position.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an improved structure for a stepper, wherein an inertial gas is filled into a hydraulic cylinder; once the compression force acting on the inertial gas is released, the inertial gas will expand, and a restoring force will be obtained; the restoring force can replace the conventional elastic elements. The present invention is free from the problem of elastic fatigue and can simplify the fabrication process and reduce the fabrication cost.

2. Description of the Related Art

Refer to FIG. 1. The conventional restoring linkage structure comprises: a rod 21, an inner sleeve 22, an outer sleeve 23, a linkage level 25, an elastic element 26, and a nut 27. The rod 21 has one threaded end 210 for screwing joint. The other end of the rod 21 is inserted into the outer sleeve 23 and functions like a piston. One end of the outer sleeve 23 has a long slot 230. Two pivot lugs 232 projects vertically from both edges of the slot 230 near one end thereof. A pivot lug 234 projects vertically from the other end of the outer sleeve 23 and aligns in a straight line with the slot 230. A screw 240 is inserted into the pivot lugs 232 of the outer sleeve 23 in order to cooperate with the knob 24 to adjust the spacing of the slot 230 of the outer sleeve 23. The inner sleeve 22 has a longitudinal slot and a flange 220 at one end thereof. The linkage level 25 is a long rod having holes at its two ends. The elastic element 26 may be a spring. The nut 27 is used to compress the elastic element 26 for increasing the damping effect.

Refer to FIG. 2 and FIG. 3. The restoring linking structure is installed in a conventional stepper. The conventional stepper comprises: a seat 10, two restoring linkage structures 20, a linking mechanism 30, and two pedals 33, 34. In the seat 10, a connecting beam 12 is used to connect a primary beam 11 and a rear beam 13. Two restoring linkage structures 20 are parallel disposed at both sides of the seat 10. Two pedals 33, 34 are pivotedly installed at both sides of the primary beam 11. The linking mechanism 30 is composed of a pulley 31 and a bull rope 32. The pulley 31 is installed below the connecting beam 12 and at the middle portion of the primary beam 11. The bull rope 32 wraps over the pulley 31, and both ends connect with two pedals 33, 34.

Refer to FIG. 1, FIG. 2 and FIG. 3. Two rods 21 are parallel spanned between the primary beam 11 and the rear beam 13, and the non-threaded ends of the rods 21 are fixedly joined with the primary beam 11, and the threaded ends of the rods 21 are fixedly joined with the rear beam 13. The inner sleeve 22 sleeves the non-threaded side of the rod 21, and the outer sleeve 23 sleeves the inner sleeve 22. The slotted end of the outer sleeve 23 is disposed near the primary beam 11 and pressed against the flange 220 of the inner sleeve 22. The elastic element 26 sleeves the rod 21, and one end of the elastic element 26 is pressed against the end having the pivot lug 234 of the outer sleeve 23, and the nut 27 is screwed into the threaded end of the rod 21 and pressed against the other end of the elastic element 26. One end of the linkage level 25 is pivotedly installed to the pivot lug 234 of the outer sleeve 23, and the other end of the linkage level 25 is pivotedly installed to the bottom of the pedal 33, or 34.

However, the conventional restoring linkage structure has the following disadvantages:

-   -   1. The energy is stored in the elastic element via         pre-compressing the elastic element. The elastic force depends         on the compressing travel, i.e. the length of the rod, which not         only occupies space but also raise the fabrication cost.     -   2. After a period of service time, the elastic element, such as         a spring or a rubber, would has elastic fatigue.     -   3. As the elastic element is installed outside, air, sunlight,         and humidity will bring about deterioration, or corrosion to the         elastic element.     -   4. The externally-disposed elastic element could probably clamp         and hurt the user.

With the persistent spirit for creation, and based on many years' experience and acquaintance in this art, the inventor has endeavored to research and study the problems mentioned above and proposes an improved structure for a stepper in order to overcome the problems.

SUMMARY OF THE INVENTION

A conventional hydraulic cylinder, which has a piston moving back and forth thereinside, can convert fluidic energy into a linear mechanical motion, and the movement of the piston can be precisely controlled within the travel of the piston. When the force acting on the piston rod is released, the conventional hydraulic cylinder needs a spring to restore it to the original state. However, a damper is usually needed to reduce the free oscillation of the bouncing-back spring. A damper utilizes a high-viscosity fluid and a small aperture to create the damping effect, and this principle is also to be adopted by the present invention to provide an improved structure for a stepper.

The conventional linkage structure with restoring effect usually adopts spring elements. Different pivots' spans or different piston travels need different springs, which is a cost burden for the manufacturer. After having been in service for a period of time, the spring could have elastic fatigue or could be corroded. Further, when using a conventional stepper, the user could be clamped and hurt by the spring.

The primary objective of the present invention is to provide an improved structure for a stepper, wherein an inertial gas together with hydraulic oil is filled into the hydraulic cylinder of a stepper, and when the force acting on the piston rod is released, a restoring force can be obtained from the expanding inertial gas in order to replace the conventional elastic elements and to enable the manufacturer to be free from preparing many kinds of springs, so that the fabrication process can be simplified and the fabrication cost can be reduced.

Another objective of the present invention is to provide an improved structure for a stepper, wherein an inertial gas free from elastic fatigue and corrosion is used to replace the conventional elastic elements, and wherein the inertial gas can be nitrogen, which is the most abundant gas in the atmosphere and is colorless, odorless and very stable and can be obtained just via utilizing nitrogen-making machine to compress the air, in order to overcome the problems of elastic fatigue and corrosion in the conventional springs and to achieve an environment-protection efficacy.

Further another objective of the present invention is to provide an improved structure for a stepper, wherein the inertial gas, which together with hydraulic oil is filled into the hydraulic cylinder, can function as a restoring and a damping devices, which are different from the conventional springs and dampers, in order to provide a more easy and comfortable performance for the user.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view of a conventional restoring linkage structure.

FIG. 2 is a perspective view of a conventional stepper with the conventional restoring linkage structure.

FIG. 3 is a side view of a conventional stepper with the conventional restoring linkage structure.

FIG. 4 is an exploded view of the improved structure for a stepper according to the present invention.

FIG. 5 is a first diagram showing schematically the operation of the improved structure for a stepper according to the present invention.

FIG. 6 is a second diagram showing schematically the operation of the improved structure for a stepper according to the present invention.

FIG. 7 is a perspective view of the improved structure for a stepper according to the present invention.

FIG. 8 is a first diagram showing one embodiment of the improved structure for a stepper according to the present invention.

FIG. 9 is a second diagram showing one embodiment of the improved structure for a stepper according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

To enable the objectives, technical contents and accomplishments of the present invention to be more easily understood, the preferred embodiments of the present invention are to be described below in detail in cooperation with the attached drawings.

Refer to FIG. 4 an exploded view of the improved structure for a stepper of the present invention. The hydraulic cylinder 50 comprises: an outer cylinder 51, an inner cylinder 52, and a piston assembly. The outer cylinder 51 is a hollow sleeve and has a diameter larger than that of the inner cylinder 52. The top end of the outer cylinder 51 has a bearing 511 having a through hole at its center, and the bearing 511 has an annular groove 512 to fix the inner cylinder 52. The bottom end of the outer cylinder 51 has a fixedly-installed connecting element 59. A joint seat 56 is disposed above the connecting element 59 and inside the outer cylinder 51. An inflation tip 57 is installed at the center of the joint seat 56 to fill the inertial gas. An O-ring 571 is installed between the joint seat 56 and the inflation tip 57 to avoid the leakage of the inertial gas. A seat 55 is fixedly installed to one end of the inner cylinder 52. Multiple notches 552 are formed on a convex rim 553 of the seat 55. The seat 55 has multiple holes 551 to let the hydraulic oil flow through. An oil-regulating wafer 554 is installed below the seat 55 to avoid too high a flow rate at which the hydraulic oil flows into the space between the outer cylinder 51 and the inner cylinder 52. Both the seat 55 and the oil-regulating wafer 554 have central holes, and a movable tip 555 penetrates those two central holes to press the oil-regulating wafer 554 to the seat 55; the movable tip 555 can float slightly. The piston assembly comprises a piston rod 53 and a piston 54. One end of the piston rod 53 has a threaded stub 531. The threaded end of the piston rod 53 penetrates the central hole of the bearing 511 at the top end of the outer cylinder 51, and a connecting element 58 is screwed fixedly to the threaded stub 531. The piston 54 is locked fixedly to another end of the piston rod 53. The piston 54 comprises multiple gaskets 541 and O-rings 542. The piston 54 and its appendixes are locked fixedly to the piston rod 53 with a nut 543. The dimensions of the piston 54 and its appendixes should enable them to fit into the inner cylinder 52.

Refer to FIG. 5 a first diagram showing schematically the operation of the improved structure for a stepper of the present invention. For the piston structure, the piston 54 is locked fixedly to the piston rod 53 with the nut 543. The other end of the piston rod 543 penetrates through the central hole of the bearing 511 to reach the exterior of the outer cylinder 51, and then is screwed fixedly to the connecting element 58. The dimension of the piston structure enables it to fit into the inner cylinder 52 and to move back and forth inside the internal cylinder 52. The seat 55 of the inner cylinder 52 exactly fronts against the joint seat 56, and the other end of the inner cylinder 52 is firmly engaged to the annular groove 512 of the bearing 511, wherein the diameter of the annular groove 512 equals that of the inner cylinder 52. When the inner cylinder 51 is assembled into the outer cylinder 51, the seat 55 of the inner cylinder 52 firmly contacts the joint seat 56, but the movable tip 555 can move or float slightly inside the central holes of the oil-regulating wafer 554 and the seat 55. At this moment, the movable tip 555 does not push the oil-regulating wafer 554 to tightly contact the seat 55; therefore the oil-regulating wafer 554 will not retard the flow of the hydraulic oil. Refer to FIG. 6 a second diagram showing schematically the operation of the improved structure for a stepper of the present invention. When a force is applied to push forward the piston 54 inside the tilting hydraulic cylinder 50, the inertial gas and the hydraulic oil are also pushed forward by the piston 54, and the inertial gas floats over the hydraulic oil. The force acting on the piston 54 compresses the inertial gas and enables the pressure inside the inner cylinder to rise, and the movable tip 555 of the seat 55 is also pushed forward to enable the oil-regulating wafer 554 to contact the seat 55. At this moment, the hydraulic oil will flow through the holes 551 and the notches 552 into the outer cylinder 51. As the oil-regulating wafer 554 can regulate the flow rate of the hydraulic oil, the inertial gas can be maintained to float over the hydraulic oil. At this moment, as the inertial gas is compressed by the piston 54, the volume of the inertial gas shrinks, and the pressure of the inertial gas rises. When the force acting on the piston 54 is released, the pressure of the inertial gas tends to expand its volume and to drive the piston back to the original position; thus, a restoring force can be obtained from the compressed inertial gas, and the inertial gas can replace the conventional elastic elements. At this moment, the movable tip 555 is loosened, and the oil-regulating wafer 554 will nor more tight contact the seat 55; thus, the hydraulic oil inside the space between the outer cylinder 51 and the inner cylinder 52 can flow back to the inner cylinder 52 through the holes 551 and the notches 552.

Refer to FIG. 7 a perspective view of the improved structure for a stepper of the present invention. The outer cylinder 51 can be seamlessly engaged with the bearing 511 and the joint seat 56 by using O-rings or roll welding in order to avoid the leakage of the hydraulic oil.

Refer to FIG. 8 and FIG. 9 showing the embodiments of the improved structure for a stepper of the present invention. The present invention can replace the convention elastic elements and can be free from elastic fatigue, corrosion, and clamping-hurt. Besides, the appearance of the present invention is free from externally-disposed elastic elements, which can further improve the appearance of the stepper.

The embodiments described above are to clarify the present invention to enable the persons skilled in the art to understand, make and use the present invention but not intended to limit the scope of the present invention. Any equivalent modification and variation without departing from the spirit of the present invention is to be included within the scope of the claims of the present invention appended below. 

1. An improved structure for a stepper, comprising: an outer cylinder; an inner cylinder, installed inside said outer cylinder; a piston assembly, further comprising a piston and a piston rod, and installed inside said inner cylinder, wherein said piston further comprises gaskets, O-rings, and a nut, and said piston is installed on the internal end of said piston rod; a seat, installed on one end of said inner cylinder; a bearing, installed inside said outer cylinder, and engaged with the other end of said inner cylinder; a joint seat, installed inside said outer cylinder, firmly contacting said seat installed on one end of said inner cylinder; and connecting elements, separately installed to the external end of said outer cylinder and the external end of said piston rod; and characterized in that a stable gas together with hydraulic oil is filled into the hydraulic cylinder to create a restoring force while the force acting on said piston is released.
 2. The improved structure for a stepper according to claim 1, wherein said stable gas is an inertial gas.
 3. The improved structure for a stepper according to claim 2, wherein said inertial gas is nitrogen.
 4. The improved structure for a stepper according to claim 2, wherein said inertial gas is helium.
 5. The improved structure for a stepper according to claim 1, wherein said hydraulic oil is a machine oil.
 6. The improved structure for a stepper according to claim 5, wherein said hydraulic oil is a mineral-oil based one.
 7. The improved structure for a stepper according to claim 5, wherein said hydraulic oil is a synthetic oil.
 8. The improved structure for a stepper according to claim 1, wherein multiple notches are formed on said seat.
 9. The improved structure for a stepper according to claim 8, wherein multiple holes are formed on said seat.
 10. The improved structure for a stepper according to claim 1, wherein said bearing and said joint seat are fixedly installed to said outer cylinder in cooperation with O-rings.
 11. The improved structure for a stepper according to claim 10, wherein said bearing and said joint seat are fixedly installed to said outer cylinder by roll welding.
 12. The improved structure for a stepper according to claim 1, wherein said connecting elements have holes.
 13. The improved structure for a stepper according to claim 1, wherein said outer cylinder and said inner cylinder are cast in carbon steel.
 14. The improved structure for a stepper according to claim 7, wherein said outer cylinder and said inner cylinder are cast in an aluminum alloy.
 15. The improved structure for a stepper according to claim 1, wherein said piston rod is chromium-plated.
 16. The improved structure for a stepper according to claim 1, wherein said gasket is made of Teflon.
 17. The improved structure for a stepper according to claim 1, wherein said O-ring is made of rubber. 